At the University of Pennsylvania we propose to study strategies for ameliorating adverse cardiovascular remodeling within the context of the Network for Cardiothoracic Surgical Interventions. Dr. Michael Acker will serve as the Principal Investigator. This proposal consists of two separate prospective randomized studies: 1) "Prospective Randomized Evaluation of Mitral Valve Repair for Functional Mitral Insufficiency and Ventricular Dysfunction" (Dr. Joseph Woo, Co-investigator) and 2) "Adjunct Delivery of Aortic Stent Graft in the Descending Thoracic Aorta in Acute Type A Dissection Repair Obliterates the Residual False Lumen and Prevents Aneurysmal Remodeling of the Distal Thoracoabdominal Aorta" (Dr. Joseph Bavaria, Coinvestigator). Each of the proposed studies addresses an important manifestation of adverse cardiovascular remodeling which currently confront cardiologists and cardiac surgeons on a routine basis. Both studies will be done in a multi-disciplinary fashion with full collaborative support from the Divisions of Cardiovascular Surgery, Cardiology, Vascular Surgery and Cardiac Anesthesiology. The principal investigator, as well as his co-investigators, has a long track record of clinical research in the fields of heart failure and aortic surgery. Each year the Division of Cardiovascular Surgery at the University of Pennsylvania performs over 1800 major procedures at three completely integrated hospitals. For the past three years we have performed 2621 valve operations and 963 thoracic aortic operations. In that same time period 1121 patients with New York Heart Association Class II, III or IV heart failure and/or an ejection fraction of<40% have had mitral valve surgery. Also in that time, 119 patients have had emergency surgery for acute type A aortic dissections. This clinical volume is more than enough for our proposed projects (MR with LV dysfunction and aortic dissection) and would represent a robust source of complex patients for any potential network study. In addition there is a research skills core that will include practical experience and didactic learning opportunities for junior faculty interested in expanding their knowledge of clinical trials and for surgical residents intending to develop primary research expertise in clinical trials. Participants in the skills core will have the opportunity to work on Network clinical trials as well as on other clinical trials within the Division of Cardiovascular Surgery. (End of Abstract)